Previously, many types of switches utilizing various actuation techniques have been in use. The photo-electric joystick switch has replaced its mechanical counterpart in applications that require high reliability, as they do not have electrical contacts that frequently burn out, as with the mechanical switches. However, thus far little work has been done to further improve the performance and longevity of the photo-electric joystick switch. Thus, the mechanical components wear out and have now become the weak link that causes failures.
This invention is of a low-cost, 8-position photo-electric joystick switch, that is versatile, durable and highly reliable, with a life expectancy that can exceed the life of the product it will become a part of.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. Pat. Nos. were considered related:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 4,748,323 Holiday May 31, 1988 4,607,159 Goodson et al Aug. 19, 1986 4,533,827 Fincher Aug. 6, 1985 4,459,022 Morey Jul. 10, 1984 4,250,378 Mutton Feb. 10, 1981 ______________________________________
Holiday uses a control shaft extending through a donut shaped, flexible, shaft-supporting mount in a narrower neck portion of a hollow casing. The shaft tilts about a vertical axis from a neutral position with the mount being relied upon for repeatability and longevity. While the mount is flexible, and no other description is given, it is obviously limited in its life and questionable as to its ability to recenter after much use. A single circuit board is taught with C-shaped support members under the board to attach the mating light detector.
Goodson et al utilize the control stick as a shutter to regulate the light falling onto the light detectors to produce control signals indicative of control stick positions. A pivot ball in a socket retains the control stick and four leaf springs engage the lowermost end of the stick to restore the stick to the centered position.
Fincher discloses a switch varying voltage through the use of a plurality of partial spheres mounted on a joystick shaft having variable light detectable surfaces. The control shaft is mounted in a ball joint with a support structure connected to a base.
Morey utilizes the angular orientation of the handle with light emitted from an optical fiber reflected from a concave mirror mounted on the handle and intercepted by a plurality of optical fibers. The intensity of light intercepted by these fibers measures the angle of the handle.
For background purposes and as indicative of the art to which the invention relates, reference may be made to the remaining U.S. Pat. No. 4,250,378 issue to Mutton.